Bolts of this type are used for securing pieces situated within a zone subject to tensile forces within a building material, for example the soffit of a concrete slab. These bolts are more particularly designed to remain sufficiently anchored, even if a crack forms inside their receiving slab zone.
A bolt of the type mentioned above is described within the document EP-A1-0 226 524. This bolt has two drawbacks. An articulated or flexion groove has to be machined inside the essential parts of the expansion ring in order to form the expansible leg portion beyond that groove.
The annular shoulder of the ring used to support the brace is provided near the plane of the ring extremity orientated towards the fixing extremity of the traction shaft so that, after expansion, the essential parts of the ring are spaced from the traction shaft substantially all along their mutual axial length between the plane of the annular shoulder and the cooperation plane between the expansible legs and the conical extremity of the traction shaft, thus creating an empty space detrimental to anchoring resistance.
The object of the present invention is to overcome these drawbacks.
Indeed, a bolt of a similar type to the one mentioned above is described within the document EP-A2-0 067 941. However, inside this bolt, the expansible legs are formed between the slits provided within the brace itself and, as in the case of the other bolt of the prior art already mentioned, beyond the articulation grooves machined for this purpose. As the expansible legs and the remaining portion of the brace have respective different functions, the unique type of material of the brace is not always adapted to any of the functions, uses, or requirements. Moreover, the anchoring resistance could sometimes prove unsatisfactory due to the expansion deficiency opposite the slits.